Self-cleaning expansible diaphragm filter



Nov. 1966 v. c. MANDAWN@ Ema.. 322329427 SELF-CLEANING EXPANSIBLE DIAPHRAGM FILTER Filed Nov. la, 196s 4 Sheets-Sheet 1 INVENTQRs /mzw QZQ f @a 2:7 ATTORNEYS @www 5 v. c. MANDAmNo ETAL, 3,2,427

, SELF-CLEANING EXPANSIBLE DIAPHRAGM FILTER Filed Nov. 18, i965 4 Sheets-sheet 2 i745 45 .55 92 44 55 96' 292@ @afg 44; 6 ,9 "fw/ m All l T; /l VB J/ f f A, f'

4.5 jf/ i 45 NOV- l, 1966 vl c, MANDARINO ETAL 3,282,427

SELF-CLEANING EXPANSIBLE DIAPHHAGM FILTER Filed Nov. 18, 1963 4 Sheets-Sheet 5 44 44 76 97 3055 92 55 45 INVENTORS 3l 95 55 37 39 Iz'zzcezz fNayzdaf/z'zzo F257; 4 Raymond la'eg v` c.. MANDARxNo ETAL 3,282,427

` SELF-CLEANING EXPANSIBLE DIAPHRAGM FILTER Filed Nov. 18, 1965 Nov. 1, 1966 4 Sheets-Sheet 4 INVENTQRs Vzlzcezz 6, [fami/@120 agmozzd Wj'o/zeci ao l ATTORNEYS United States Patent O 3,282,427 SELF-CLEANING EXPANSIBLE DIAPHRAGM FILTER Vincent C. Mandarino, St. Joseph, and Raymond W. Spiegel, Stevensville, Mich., assignors to Whirlpool Corporation, St. Joseph, Mich., a corporation of Delaware Filed Nov. 18, 1963, Ser. No. 324,324 16 Claims. (Cl. 210-108) This invention relates generally to filtering -apparatus and more particularly to a self-cleaning expansible diaphragm filter for an automatic Washing machine having a reversible hydraulic -circuit for circulating laundry liquid first in one direction during a washing operation and then in an opposite direction during an extracting and draining operation.

In accordance with the present invention -an exemplary automatic clothes washing machine operable through a complete cleaning cycle including washing, extracting and draining operations, is provided with a self-cleaning filter connected in the hydraulic circuitry and in fluid communication with the pump such that the filter is located on the suction side of the pump during a wa-shing operation and on the pressure side of the pump during anV extracting and draining operation.

The filter comprises a resilient, flexible wall member Vor diaphragm having an irregular surface on the inner face thereof and which is subjected on the outer face thereof to atmospheric pressure. The flexible Wall member is capable of being urged into abutting engagement with an associated rigid wall member of coextensive area which includes another irregular surface on the inner face thereof, thereby forming a filter maze or la honeycombed baflle system. When laundry liquid is circulated through the filter it passes between the tortuous restricted filter path prescribed by the irregular surfaces of the two wall members. During a washing Ioperation when the filter is connected to the suction side of the pump the fluid pressure within the filter is reduced to a pressure less than atmospheric so that flexible wall member is thereupon urged into abutting engagement with the rigid wall member by the force of atmospheric pressure acting thereon and the irregular surfaces of the two inner faces of the two wall members form small orifices comparable to a filter mass through which the liquid must pass. Any lint or other foreign particles being carried in the liquid stream are entrapped in the orifices thus created and are separated from the liquid.

During an extracting and draining operation when the filter is connected to the discharge side of the pump, the flexible wall member is urged away from the rigid wall member, thus eliminating the small orifices and allowing the laundry liquid to flow over the irregular surfaces in a state of turbulence to cleanse and flush the filter.

Another object of the present invention is to provide an expansible self-cleaning filter which assumes a contracted state configuration when liquid is flowing therethrough under negative pressure to filter th-e liquid and assumes an expanded state configuration when the liquid is flowing therethrough under positive pressure to effectively clean and flush the filter.

Another object of the pres-ent invention is to provide a self-cleaning filter `for an automatic washing machine, the variance in fluid pressure which exists therein automatically resulting in the engagement of filtering surfaces for filtering liquid when the liquid is flowing therethrough under negative pressure and in separating the filtering surfaces when the liquid is flowing therethrough under positive pressure to clean and to flush the filter.

Another object of the present invention is to provide a self-cleaning filter for an automatic washing machine which is adapted to form small orifices therein through ICC which laundry liquid must pass when the liquid is circulated under negative pressure through the filter for entrapping lint and the like material immersed in and carried by the liquid, and which is adapted to eliminate the small orifices when the liquid is circulated under positive pressure through the filter for releasing and removing the lint and the like material from the filter for cleansing and flushing the filter.

And yet another object of the present invention is to provide a self-cleaning filter for an automatic washing machine which is efiicient in operation, simple but rugged in construction, inexpensive in manufacture, is self-cleaning and requires no moving parts.

Many other features, advantages and additional objects will become manifest to those versed in the art from the detailed description of the invention which follows and the accompanying vsheets of drawings in which a preferred embodiment of a self-cleaning filter incorporating the principles of the present invention is shown by way of illustrative example.

On the drawings:

FIGURE 1 is a -bottom plan view of the self-cleaning filter of the present invention;

FIGURE 2 is a top plan view of the filter of FIG- URE 1;

FIGURE 3 is a cross-sectional View of the filter taken substantially along lines III-III of FIGURE 2;

FIGURE 4 is a cr-oss-sectional view of the filter taken substantiallyalong lines IV-IV of FIGURE l;

FIGURE 5 is a top plan view of the filter body portion;

FIGURE 6 is a fragmentary, plan view of the flexible wall member or diaphragm of the present invention and illustrates the lands and grooves in the inner face thereof;

FIGURE 7 illustrates a fragment of the filter body portion as illustrated in FIGURE 5 and shows diagrammatically the lands and grooves of the diaphragm superimposed thereon in thin phantom line;

FIGURE 8 is an enlarged fragmentary cross-sectional view 4of the diaphragm of FIGURE 6 illustrating the configuration of the lands and grooves formed on the inner face thereof;

FIGURE 9 is a substantially diagrammatic view of the Ihydraulic circuitry of an automatic washing machine incorporating therein the self-cleaning filter of the present invention; and

FIGURE 10 is a diagrammatic view incorporating the filter of the present invention in a unidirectional arrangement.

As shown on the drawings:

Although the principles of the present invention are of general utility, a particularly useful application is made to automatic washing machines. An illustrative embodiment herein shown consists of an agitator type automatic washing machine shown generally at 10 having a vtreatment zone 15 comprising an imperforate tub 11 and a perforate wash basket positioned therein as at 12. An agitator of the vertical-axis type is shown at 13, but it will be understood that the principles of the present invention are applicable to a washing machine incorporating other types of washing mechanisms, such as horizontal-type agitators or rotating drum baskets, and also find utility in filtering liquids in any other apparatus incorporating a circulating hydraulic circuit.

Disposed below a bottom wall 14 of the tub 11 is a laundry liquid or fluid pump 16 of Ithe reversible flow type. Anelectric motor M is shown diagrammatically at 17 and is operatively connected to the agitator 13 and the pump 1'6 as at 18. The motor M is energized and controlled by the automatic sequential control circuitry of a sequential control means.

The pum-p 16 has a pair of fluid openings 19 and 20,

the opening 19 being in fluid communication with the in 3 terior of the tub 11 through a conduit 25 and a trap 21 which is connected -to an opening 22 formed in the bottom wall 14 of the tub 11.

In accordance with the present invention the outlet of the pump 16 discharges through a self-cleaning filter y23. In order to direct the flow through the filter conduit means are provided including a conduit 35, a conduit 24 and a check valve as at 26. The check valve 26 has an opening 27 which is in fluid communication with the tub 11, an opening 28 which is in fluid communication with the conduit 24 and an opening 29 which is in iiuid communication with a drain conduit 30. The drain conduit 30 is connected to a sewer drain for disposing of soiled -laundry liquid in the usual manner.

In the plumbing diagram of FIGURE 9 the solid arrows represent the direction of fiow of the laundry liquid through the hydraulic circuitry during a washing operation. In this respect, the check valve 26 incorporates a ball check 31 which is positioned automatically by fluid flow to allow fluid flow through opening 27 and opening 23 in the direction of the solid arrows during a washing operation. Accordingly, du-ring a washing operation, the pump 16 wil-l draw Iliquid from the tub 11 via the opening 27 of the check valve 26, lthe conduit 24, the filter 23, and the conduit 35. The laundry liquid is discharged through the pump opening 19 into the conduit 25, from whence it passes through the trap 21, the tub opening 22 land back into the tub 11.

The direction of flow of the laundry' liquid during an extracting and draining operation is shown by the broken arrows. Laundry liquid from the tub 11 is drawn by the pump 16 through the opening 22 of the bottom Wall 14 .into the trap 21, from whence it flows through the conduit to the opening 19. The laundry liquid is discharged from the pump 16 through the pump opening 20 into the conduit 35, through the filter 23, the conduit 24, and the check valve 26, and is discharged to drain through the drain conduit 30. During the extracting and draining operation, ball check 31 prevents the fluid from flowing through opening 27.

Referring to FIGURES 1, 2 and 3, the filter comprises a shallow or flat annularly shaped, housing 33 having one end wall which comprises -a lower member or filter body portion 34 and a second end wall which comprises an upper member or resilient diaphragm 36. In the embodiment illustrated, the body portion 34 constitutes a rigid, non-resilient member material such as a clear plastic or the like. The diaphragm 36 constitutes a flexible, elastic material, such as rubber or the like, which is susceptible to a fiexing or bellowing action when acted upon by the various hydraulic pressures to which the filter is subjected during operation thereof.

In order to ensure uniform flexure across the 'entire face of the diaphragm 36 a thin, rigid, annularly shaped backing plate or diaphragm support member 37 is bottomed against the outer face 38 of the diaphragm 36. In order to maintain sufficient force of the diaphragm support 37 against the diaphragm 36 to retain the diaphragm 36 in filtering relation with filter body portions 34 in the absence of negative pressure created by the pump, a pair of flexible spring clips 45, 45 are wrapped around the filter housing 33 and engage an outer face 39 of the diaphragm support 37 and an outer face 41B of the filter body portion 34 .in a snug but light inwardly pressing relation.

The spring clips 45, 45 are prevented from moving laterally along the outer faces 39 and 4t) of the diaphragm support 37 and the body portion 34, respectively, by means of a series of lateral grooves formed therein. A pair of spaced parallel elongated boss mm'ebers 41, 41 are formed on the outer face 40 of the filter body 34 and form a pair of grooves 42, 42 which receive end portions 43, 43 (FIG- URE 4) of the spring clips 45, 45. A `pair of raised portions 44, 44 are formed on the outer face 39 of the diaphr-agm support 37 and comprise respectively therebe- 4 tween a pair of grooves 46, 46 which receive middle portions 47, 47 (FIGURE 4) of the spring cli-ps 45, 45.

Extending perpendicularly downwardly from the outer face 4@ of t-he filter body portion 34 are a pair of spaced, cylindrically shaped duct members 49 and 50 connected to the conduit members 35 and 24 illustrated in FIGURE 9 for directing laundry liquid into and out of the filter housing 33. In order to facilitate rapid, easy connection of the conduits 35 and 24 to the ducts 49 and 50, respectively, connector portions or enlarged diameter, expansion-fit, tapered heads 52 and 53 are formed at distal ends 54 and 56 of the ducts 49 and 5t). The conduits 35 and 24 are connected to the ducts 49 and 50 by urging an open end of the conduits 35 and 24 over a corresponding enlarged head 52 or 53 of the ducts 49 and 5t). Due to the resiliency of the flexible yconduits 35 and 24 they will be urged by a radially inward bias to conform in tight pressing engagement to the configuration of the duct body portions as at 51 -and the duct heads as at 52 and 53. Of course, hose clamps or suitable means may be used to effect a clamping action of the hoses to the ducts if desired.

As best illustrated in FIGURES 3 and 5, the filter body portion 34 comprises a fiat inner face as at 57 having formed thereon projecting upwardly and outwardly a plurality of arcuately shaped radially spaced liquid deflectors or rib members 58. Each of the rib members 58 comprises a pair of radially vspaced complementarily shaped side walls 59 and 60 so that adjacent rib members form arcuately shaped channels as at 61 and 62 respectively having bottom walls 63.

In order to form a tortuous filter path which will separate material to be filtered from the liquid stre-am, a series of baffie members are formed on the inner face 57 of the body portion 34 and are arranged to interconnect adjacent side walls 59 and 60 of the rib members 58 at alternate ends of adjacent channels. For example, baffle end members 66, 67, 68, 69 and 70 are illustrated as ea-ch interconnecting a pair of adjacent side walls 59 and 60 at one end thereof as vat 71. The bafiie end members 66-7 0 a-re arranged such that alternately spaced channels are in open communication with the duct 49, thereby serving as entrance walls.

Another series of baffle end membre-rs 72, 73, 74, 75 and 76 are arranged to interconnect pairs of side walls 59 and 60 at ends thereof opposite the ends 71, such as at 77. However, exit walls 72, 73, 74, 75 :and 76 do not interconnect any pair `of side walls 59 and 60' that are interconnected by baflie end members 66-70. The

exit walls 72, 73, 74, and 76 prevent direct fiow from the duct 50 from any of the channels as at 62 and 62a that `are in `open communication with duct 49. Any of the channels that are not in open communication with the duct 49 are connected at their opposite end with the duct 50. Laundry liquid which enters the filter housing 33 through the duct 50 can only -flow int-o every other channel. Further, the channels into which the laundry liquid can directly fiow from duct 5t) are closed at their opposite ends as at 72, 73, 74, 75, thereby preventing direct effluence therefrom into duct 49.

l FIGURES 3 and 4 illustrate the relative position of the diaphragm 36 and the filter body portion 34 during a washing operation while laundry liquid is entering the filter housing 33 through the duct 50. A ci-rcularly shaped serrated inner face 78 of the diaphragmy 36 is shown as confronting in abutting engagement the side wal-ls as at 59 and 60 of the body portion 34. The upper edges of the side walls form flat surfaces as at 79, all of which lie in a single plane which is in parallel relation to the inner face 57 of the body portion 34.

A fragment-ary plan View of the inner face 78 of the diaphragm 36 is illustrated in FIGURE 6 and comprises a series of serrations or grooves as at 3f) which are grouped essentially into four quadrants of the circularly shaped diaphragm 36. All of the grooves in each of the four quadrants `are arranged in spaced parallel relation. Each inner face 78 fangularly spaced by 90, and extend to a circula-rly shaped perimeter 81 of the inner face 78.

As shown in FIGURE `8, each of the grooves 80 has a pair of upwardly -angul-a-rly extending groove walls 82 and 83 which intersect each .other substantially at right angles :and is separated from adjacent grooves |by a pair of spaced parallel lands as at 84, comprising a flat bottom wall as at 86. During a washing operat-on, when the configuration of the filter housing 33 is as illustrated in FIGURES 3 and 4, the bottom walls 86 of the grooves 80 and the flat surfaces 79 of the side walls 59 and 60 are copla-nar.

The filter body 34 and the diaphragm 36 are adapted to facilitate quick, snap-fit assembly, and for this purpose the filter body 34 comp-rises and upsta-nding circumferentially continuous peripheral wall 87 having an arcuately shaped upper surface `88 and a recessed portion 8.9 forming an outturned shoulder member as at 90.

The diaphragm 36 comprises a peripheral flange portion as at 91 having an upwardly angularly arcuately shaped transistion portion as at 92 which extends upwardly to and overlies the upper surface 88 of the body 34. An inner face 93 of the transition portion 92 is shaped complementarily to t-he peripheral wall 87 and comprises an annularly shaped boss 94 having an intu'rned shoulder member las at 96 in abutting relation with the shoulder 90 of the peripheral wall 87.

To mount the diaphragm 36 on the filter body 34, the flange portion 91 of the diaphragm 36 is urged outwardly over and around the peripheral Wall 87 and inwardly until the boss 94 is positioned adjacent the recessed portion 89, and snaps the shoulder 96 into contiguous abutting engagement with the shoulder portion 90.

It may be desirable to provide means for applying a greater radially inward -bias of the flange member 91 than that which results from the natural or inherent resiliency of the Idiaphragm 36, and for this purpose a recess 97 is formed in the outer face 98 of the flange member 91 rand extends around the perimeter of the outer face 98, to receive a steel strap.

In FIGURE 7 the grooves ySil of the diaphragm 36 are shown superimposed over the filter body 34 substantially transversely in relation to the rib members 58.

During the agitation portions of the wash cycle, the fluid is reci-rcuated through the machine in the direction as shown by the .solid arrows (see FIGURE 9) thus placing the filter 23 on the suction side of the pump 16.

When the pump 16 takes :a suction on the line containing the filter during the agitation portion of the wash cycle, the fluid pressure of the liquid Within the filter housing 33 is reduced to a pressure subst-antially less than atmospheric. This reduction of pressure internally of the filter housing 33 causes pressure of the ambient air externally thereof to urge the diaphragm 36 into abutting engagement with the filter body 34,' thereby keeping the various passages in a to-rtuous lhoneycombed relation to chan-ge the direction of the liquid anddevelop a good separating action.

As the laundry liquid enters the duct 50 it is directed into various channels indicated by the reference B (FIGURE 7). Since channels B are not in open communication with the duct 49, and since alternate channels A are in communication with duct 49, the laundry liquid w-ill Iflow therebetween through the only flow passageway available, that is, through the grooves 80 and into channels A, from which it is discharged through the duct 49.

Foreign particles will not flow through the grooves 80 due to the reduced cross-sectional area thereof and become entrapped within the filter at the juncture of the flat surfaces 79 of the rib members 58` and the grooves 80.

Divider walls 101 and 102 are formed in the filter body 34 adjacent the duct 49 in order to .prevent the collapsing of the resilient diaphragm 36 into the outlet 49 when the filter is under negative pressure.

During the extraction and drain portion of wash cycle the fluid is pumped from the `machine as shown =by the broken arrows (see FIGURE 9).

Because the filter 33 is then on the discharge side of the pump 16 and liquid is supplied to the filter under pressure and the diaphragm 36 is flexed outwardly away from the filter body 34.

The laundry liquid flows directly from the duct 49 to the duct 50, but the grooves and the rib members 5S create ia state of turbulence of the liquid within the filter 33 which loosens the trapped lint `and other foreign particles and entrains the same in the liquid stream.

Summarizing, the filter is placed in the fluid circuitry i of an automatic washing Imachine in such a manner that during the portion of the cycle that the washing fluid is frecirculated within the machine,` the interior of the filter housing 33 is under negative pressure. Being under negative pressure, the resilient diaphragm 36 is drawn into abutting engagement with the filter body 34 thereby forming -a tortuous honeycomb filter path for the recirculating fluid. At the end of the recirculating lwashing period, the fluid is pumped from the machine during t-he draining Operation. The filter housing 33 is located in the fluid circuit in such a manner that during the draining operation the interior of the filter housing 33 is subjected to a positive pressure of the fluid, thereby forcing the flexi-ble diaphragm 36 out of abutting engagement with the filter body 34. The removal of the flexible diaphragm 36 from t-he abutting engagement with the filter body 34 effectively opens the filter and allows the draining fluid to be flushed 'ac-ross the filter elements :thus flushing the previously entrapped particles from the filter housing 33 into the drain.

It Will be appreciated that the self-cleaning filter of the present invention may -be utilized in a unidirectional hydraulic arrangement as well as the reverse flow :arrangement of FIGURE 9. For example, FIGURE 10 illustrates a plumbing diagram incorporating a filter 23a of the present invention whereby the direction of flow of laundry liquid through the filter i-s the same for lthe wash cycle of the automatic washing machine, during which the filter entraps foreign particles -being circulated with the liquid, and for the drain cycle, during which the entrapped particles are flushed from the filter to clean the filter.

Referring to FIGURE 10, during a wash cycle the laundry liquid may be circulated from the tub through conduits 24a and 24b, through the pump 16a and Iback to the tub through conduit 25a. Interposed between conduits 24a and 24b is the filter 23a which is connected at one opening 50a thereof to conduit 24a and which is connected at a second opening 49a thereof to conduit 24h. A pair -of check valves and 111 are installed -in conduit 24a as shown, with the direction of flow therethrough as indicated by the arrows. Another check valve 112 is installed in conduit 2417 and a conduit 30a leading to a suitable drain is shown connected to conduit 24b.

During a wash cycle, the laundry liquid flows in the direction indicated by the dashed lines, that is, through conduit 24a, then through the filter 23a, and thence through conduit 24b to .the pump 16a, from which it is circulated back to the tub. It will be noted that during this period the interior of the filter 23a is under negative pressure and foreign particles in the liquid will be entrapped therein.

During a draining cycle, the laundry liquid flows in the direction of the solid lines, that is, from the tub through conduit 25a, the pump 16a and the filter 23a to be discharged to a suitable drain through conduit 30a. It will lbe noted that during this period the laundry liquid flows through the filter 23a in the same direction as during ra wash cycle, only now the interior -of the filter is under a positive pressure, whereby the entrapped particles are flushed from the filter back into the laundry liquid to be circulated to the drain.

Accordingly, there has thus been provided a filter which 7 is simple in construction, efficient in operation, and is entirely self-cleaning.

Although vari-ous modifications might be suggested by those versed in the art, I wish to embody within the scope 8 subjected to an internal pressure greater than the pressure external of `said assembly when the liquid flow is in said one direction, and an internal pressure less than the pressure external of said assembly of the patent warranted hereon all such modifications as when the liquid flow is in said opposite direction and come within the scope of my contribution to the art. comprising,

The embodiments of the invention in which an exclusive a rigid housing having an action surface, property or privilege is claimed are defined as follows: a flexible member having an irregular Surface 1. In cleaning apparatus, mounted -on said housing and flexing toward means forming a hydraulic circuit including a treatl0 Said aerien surface when the liquid is drawn ment zone and a pump for circulating liquid from by the pump through the filter and circulated the treatment zone through the circuit and Iback to unde-r said lesser internal pressure between said the treatment zone first in one direction and then in housing and Said flexible rnernber, an Opposite direCtiOIl, the irregular surface of said flexible member and a hollow enclosed fluid-tight self-cleaning filter mounted said action surface forming multiple liquid lioW in the Circuit between the tfatment Zone and the ,passages therebetween of restricted Size to en. pump and having a first impervious wall member trap foreign .particles from the liquid, Which S Stationary and 1a Second mPefVOUS Wall said flexible member flexing away from said action member which is movable toward said first wall mem- Surface when @ne liquid is circulated under Said bef When `the Pressure III the Interior 0f the ltel' iS 20 greater internal pressure between housing less than the pressure outside of said filter to form and Said flexible inem-ber thereby te ferm a a filter maze within said filter and movable away through passage and releasing the foreign parfrom said first Wall member when the pressure in unies entranped therein into the liquid the interior of said filter is greater than the pressure 4 Fm .use in Cleuning apparatus, outside of said filter to eliminate the filter maze, a Selpcleaning nlter comprising,

lsaid second wall member moving toward and ada rigid housing having a pair of Openings adapted jacent to said first wall member when the launio Ihe connected in liquid HOW series in a hydry liquid is circulated -through the interiorpof riiauliC circuit, said filter in one d1rect1on and on the suction means duiiuing a surface ii.1 Said housing having a 51de 0f the Pump t0 fQfm the mier maze ffr 30 rib member intermediate said openings to imentrapping foreign particles which may be cirpude liquid liOW therebetween, culated with the liquid within said filter, and a llexible member lhaving an irregular surface Sa'id Second Wan member moving awayfrom mounted on said housing and adapted to flex said rst wall member when the liquid is Cllr* toward said surface and abut said rib member culated through `the interior of said filter in said when the liquid is circulated under a pressure Opposite diremo? and on the discharge Side of between said housing and said flexible member Sald Pump to ehmmate the lter maze 3nd,t0 at less than the pressure external thereto, fom? a through Passage for releasmg forelgn the irregular surface of said flexible member and particles entrapped within the filter and for Said rib member forming liquid flow passages Cleamng the lter; 40 therebetween to entrap foreign particles from 2. In an automatic washing machine, the liquid means forming a hydraulic circuit including :a treat- Said hexible member adapted to hex away from ment zone and a pump for circulating laundry liquid Said housing into a spaced relation to Said rib from the treatment zone through the circuit and Iback member when the liquid is circulated under a to the treatment zone first in one direction and then pressure ,between Said housing and said exlble in an opposite direction, and 45 a hollow enclosed fluid-tight self-cleaning filter mounted in said circuit for circulating the laundry liquid through the interior thereof Iand subjected to an internal pressure which is less than the pressure exmember greater than the pressure external thereto to form a through passage in the filter thereby by eliminating said liquid flow passages and releasing the foreign particles entrapped therein.

ternally thereof when flow is in said one direction and -to `an internal pressure which is greater than the pressure externally thereof when flow is in said opposite direction and comprising,

a rigid impervious housing having an inlet and an outlet connected to said circuit,

5. The invention as defined in claim 4 further characterized by said irregular surface having a plurality of grooves.

6. For use in cleaning apparatus,

a eresilient self-cleaning filter assembly for mounting liquid flow imposing means disposed within said housing, and a flexible impervious member connected t-o said housing adjacent said flow imposing means and movable toward and adjacent yto said flow imposing means to form a filter maze therewith for entrapping foreign particles from the liquid when the liquid is circulated in said one direction through said housing and movable away from said flow imposing means to eliminate said filter maze and to release foreign particles into the liquid when the liquid is circulated in said opposite direction through said housing. 3. In cleaning apparatus, means forming a hydraulic circuit including a treatment zone and a pump for circulating liquid from the treatment zone through the circuit and back to the treatment zone first in one direction and then in an Vopposite direction, and a self-cleaning filter assembly mounted in said circuit in a liquid ci-rcuit and having a contracted state and an expanded state when the liquid is circulated t-hrough the filter assembly under an internal pressure less than the pressure external of said assembly and then under an internal pressure greater than the pressure external of said assembly respectively, and comprising,

a housing having first and second openings adapted to be connected in liquid flow series in the circuit,

first rib members formed in said housing and defining a first channel in open fluid communication with said first opening and in closed fluid communication with said second opening,

second rib members formed in said -liousing and defining a second channel in open flluid communication with said second opening and in closed fluid com-munication with said first openmg,

a flexible member having a plurality of lands and grooves formed thereon mounted on Isaid housing, said lands abutting said rib members substantially transversely thereof to form a plurality of fluid flow passages therebetween for communicating said first and second openings and for entrapping foreign particles therein when said filter is in said contracted state, and

said lands assuming a spaced 'relation to said rib members when said filter is in said expanded state to forma through passage and eliminate said flow passages and release t-he foreign particles entrapped therein.

7. In a cleaning machine having a reversible hydraulic circuit, the improvement of a resilient self-cleaning filter mounted in the circuit and having a contracted state configuration and an expanded lstate configuration depending on the amount of pressure within the filter a-s determined by the direction of flow of liquid in the circuit, said filter comprising,

an expansible filter housing having a pair of interfacing end walls,

a :pair of ducts formed in said housing and connected in hydraulic series with the circuit for directing liquid into and o-ut of said housing,

means defining a plurality ,of rib members formed on one o'f said end wal-ls,

said rib members dening a .pair of elongated channels arranged in side-by-si-de relation and in communication wit-h the other of said end walls and with said ducts,

means defining baffle wal-1s formed on said one of said end walls and extending transversely `between said rib members at the ends of -said channels,

said baille Walls closing one end of said channels to one o-f said ducts and closing one end of the other of said channels to the other of said ducts, and

means defining a plurality of lands formed on the inner lface of the other of said end walls and extending transversely of said rib member and abutting said rib members to form restricted liquid flow passages therebetween when the liquid is circulated under a pressure through said filter lhousing which is less than the pressure external thereto to thereby contract said filter and movable away from said rib members to form a through passage and eliminate the liquid flow passages when the liquid is circulated under a pres-sure through said filter housing which 4is greater than the .pressure external thereto to thereby expand said filter.

8. In a cleaning machine having a :hydraulic circuit includi-ng a treatment zone and means for circulating liquid alternately in opposite directions in said circuit, a self-cleaning filter assembly mounted in the circuit for filtering foreign particles from the liqui-d when t-he liquid is circulated throughsaid filter assembly under a pressure less than the pressure external of said assembly and for effecting self-cleaning when t-he liquid .is circulated through said filter under a pressure greater than the pressure external of said assembly, said filter assembly comprising,

a filter body having a pai-r fof ducts connected in series with said circuit 'for directing liquid into and out 0f said filter, V

means forming an end wall on said filter body,

means forming a plurality of rib members on said end Wall and arranged in spaced side-by-side relation,

said rib members :projecting from the inner face of said end wall and forming elongated channels therebetween,

a flexible diaphragm mounted on said body opposite Vsaid end wall, v

means defining a plurality of lands formed on the inner face of said diaphragm and disposed transversely to said rib members,

said channels being in open communication with 10 the inner face of said diaphragm and with said ducts,

baffle members formed on the inner face of said end wall and interconnecting said rib members at the ends o'f said channels to close every other channel Vto 4one o'f said ducts and close the remaining channels to the other of sai-d ducts,

said diaphragm being flexed inwardly toward the inner face of said end wall when liquid is circulated through said filter under a pressure which is less than the pressure external thereto to effect abutting engagement of said lands with said rib members to thereby form restricted liquid flow passages therebetween and being flexed outwardly away from the inner face of said end wall when liquid is circulated through said filter under a pressure which is greater than the pressure external thereto to 'form a through passage and thereby eliminate said flow passages. a

9. A self-cleaning liquid filter adapted for connection in a hydraulic circuit having circulating means for circul-ating liquid in the circuit in opposite directions, said filter comprising,

a filter body having a flat end wall,

a pair of duct-s formed in spaced relation in said body for directing lliquid into and out of said filter,

a plurality Iof rib members formed on the inner face of said end wall and arranged in side-by-side spaced relation,

a flexible diaphragm mounted on said body opposite the inner face lof said end wall,

said rib members forming channels therebetween in open communication with the inner face of said diaphragm and with said ducts,

a plurality of lands formed on the inner face of said diaphragm to form a plurality of grooves therebetween arranged transverse-ly with said rib members,

baille walls formed on the inner face of said end wall and interconnecting said rib members at the ends of said channels to close some of said channels to one of said outlets and to close the remaining channels to the other one tof said outlets,

a diaphragm support shaped comp'lementarily to the outer'face of said diaphragm and abutting thereagainst,

Iresilient means mounted on said body and engaging said diaphragm support for urging said support into engagement with said diaphragm,

said diaphragm being flexed inwardly toward the inner face of said end wa-ll when the filter is connected to the suction side of said circulating means 'for effecting abutting engagement of the lands thereon With said rib members to form liquid flow passages in said grooves, and said diaphragm bein-g flexed outwardly away from the inner face of said end wallwhen the filter is connected to the discharge side of said circirculating means for moving said lands away from said rib members to lform a through passage for eliminating said liquid flow passages, whereby the flexing move-ment of the diaphragm is effected by variation in hydraulic pressure within the filter as the connection of the filter to the circulating means is alternately changed from the disch-arge to the suction side thereof.

10. A self-cleaning liquid filter adapted for connection in a hydraulic circuit having circulating means for circulating liquid in the circuit in opposite directions, said filter comprising,

' a generally circularly -sh-aped filter body having a substantial-ly flat end wall,

a pair of ducts for directing liquid into and out of said filter disposed respectively `on opposite sides of said end wall,

l l a plurality of arcuately shaped radially spaced rib members formed on the inner face of said end wall, each of said rib members having a substantially fiat top surface, all of said top surfaces lying in a 4plane disposed in spaced parallel relation to said end Wall,

a substantially flat fiexible diaphragm mounted on the filter body around the periphery thereof and extending over the inner face .of said end wall,

the inner face of said diaphragm and said flat surfaces positioned in proximately 4spaced parallel relation,

said rib members forming channels therebetween in open -communicat-ion wit-h the inner f-ace of said diaphragm,

bafiie walls formed on the -inner face of said end wall and transversely interconnecting said rib members at the ends of said channels to close some of said c-hannels to one of sai-d ducts and to close the remaining channels to the other one kof said ducts,

a plurality of lands formed on the inner face of said diaphragm,

said lands disposed 4in spaced relation to form grooves therebetween and arr-anged substantially transversely to said rib members,

a diaphragm backing plate shaped complementarily to the outer face of said diaphragm and abutting thereagainst,

a plurality of spring clips extending around said filter and engaging the outer -faces of said filter lbody and said backing plate for urging said backing plate into abutting engagement with said diaphragm,

said diaphragm being flexed inwardly toward the inner face of said end walls when the filter is connected to lthe suction side of said circulating means for effecting abutting engagement of the lands thereon with the fiat surfaces of said rib members to form liquid fiow passages therebetween, and said diaphragm being flexed outwardly away from the inner face of said end wall when the filter is connected to the discharge side of said circulating means for moving said lands away from said flat surfaces of said rib members to form a through passage and eliminating said liquid flow passages, whereby the flexing movement of said diaphragm is effected by variation in hydraulic pressure within the filter as the connection of the filter to the circulating means is alternately changed from the discharge to the suction side thereof.

11. A fiuid filter for filtering the foreign particles from a fluid comprising,

two openly facing walls having filtering surfaces defining a filter area,

said walls adjoined at the outer periphery thereof, means defining an opening in one of said walls to form an inlet to said filtering area,

means defining an opening in one of said walls to form an outlet from said filtering area,

at least one of said walls being made of elastic material and being movable into abutting relationship with the other of said walls,

said walls being in abutting relationship thereby defining a filtering surface when said openings are subjected to a negative pressure, and said walls being in spaced relationship thereby defining an open conduit when said openings are subjected to a positive pressure.

12. A fluid filter for filtering the foreign particles from a fiuid comprising,

a pair of interfacing walls adjoined at the periphery thereof to define a filter chamber and having complementary filtering surfaces formed thereon, and

a pair of openings formed in said walls to provide a Cil fiuid inlet into and a fiuid outlet out of said filter chamber,

at least one of said walls being made of fiexible material and fiexed into and out of abutting engagement with the other of said walls, the filtering surfaces of said flexible wall being fiexed into abutting engagement with the filtering surfaces of said other wall to filter foreign particles out of the fluid passing through said chamber when the pressure within said chamber is less than the pressure external thereto, and the filtering surfaces of said ffexible wall being fiexed out of abutting engagement with the filtering surfaces of said other wall to form an open conduit between said inlet and said outlet to recirculate filtered particles back into the fiuid passing through said chamber to clean and to flush said filtering surfaces when the pressure within said chamber is greater than the pressure external thereto. 13. In a washing machine cyclically operable through a washing cycle and a drain cycle,

means forming a hydraulic circuit including a treatment zone and a pump for circulating liquid from the treatment zone through the circuit and back to the treatment zone, and a self-cleaning filter comprising a plurality of confronting completely impervious walls defining a hollow fluid-tight filter body having a filter chamber therewithin, means providing a pair of fiuid parts in said filter body connected into said hydraulic circuit and communicating with each other through said chamber for circulating liquid through said chamber,

said walls being relatively movable into adjacent relation with each other and also being relatively movable into substantially spaced relation with each other, filter means within said chamber and between said walls and being activated when said walls are in said adjacent relation to filter fiuid circulated through said chamber and being deactivated when said walls are in said spaced relation, and means operative during the washing cycle for moving and maintaining said walls in said adjacent relation and operative during the drain cycle for moving and maintaining said walls in said spaced relation for flushing of said filter means. 14. In a cleaning apparatus,

means forming a hydraulic circuit including a treatl ment zone and pump means for circulating liquid alternatively in opposite directions from the treatment zone through the circuit and back to the treatment zone, and a hollow enclosed fluid-tight filter having a pair of fluid ports connected in said circuit for circulating the liquid through the interior of said filter,

said filter comprising a pair of impervious confronting adjacent walls having fiat inner faces and mating bafiie means thereon movable toward one another when the circulating liquid enters said filter through one of said ports to form a tortuous filter path and movable away from one another when the circulating liquid enters said filter through the other of said ports for self cleaning said filter. 15. A self-cleaning filter for use in a washing machine having a washing cycle and a drain cycle, comprising a plurality of confronting impervious walls defining a hollow fiuid-tight filter body having a filter chamber therewithin, means providing a pair of fiuid ports in said body communicating with each other through said chamber for circulating fluid through said chamber,

said walls being relatively movable into adjacent relation with each other and also being relatively movable into substantially spaced relation with each other,

lter means within said chamber and between said Walls and being activated when said walls are in said adjacent relation to filter fluid circulated through said chamber and being deactivated when said walls are in said spaced relation, and

means operative during the washing cycle for moving and maintaining said walls -in said adjacent relation and operative during the drain cycle for moving and maintaining said walls in said spaced relation for iiushing of said ilter means.

16. A self-cleaning uid filter comprising a plurality of confronting impervious walls forming a hollow fluidtight filter body having a chamber formed therewithin,

means forming a fluid inlet and a fluid outlet on said body communicating with each other through said chamber,

one of said walls moving toward and adjacent to another said confronting wall when the pressure within said chamber is less than the pressure outside of said body and moving away from said another confronting wall when the pressure within said chamber is greater than the pressure outside of said body, and means formed on said one of said walls and on said another confronting Wall to form uid filter means within said chamber when said one of said walls moves toward and adjacent to said another confronting wall and to eliminate said iuid iilter means within said chamber when said one of said walls moves away from said another confronting Wall.

References Cited by the Examiner UNITED STATES PATENTS 2,221,210` 11/1940 Soderquist 210-356 X 3,179,116 4/1965 Jacobs 210-3'56 REUBEN FRIEDMAN, Primary Examiner.

D. M. RIESS, Assistant Examiner. 

14. IN A CLEANING APPARATUS, MEANS FORMING A HYDRAULIC CIRCUIT INCLUDING A TREATMENT ZONE AND PUMP MEANS FOR CIRCULATING LIQUID ALTERNATIVELY IN OPPOSITE DIRECTIONS FROM THE TREATMENT ZONE THROUGH THE CIRCUIT AND BACK TO THE TREATMENT ZONE, AND A HOLLOW ENCLOSED FLUID-TIGHT FILTER HAVING A PAIR OF FLUID PORTS CONNECTED IN SAID CIRCUIT FOR CIRCULATING THE LIQUID THROUGH THE INTERIOR OF SAID FILTER, SAID FILTER COMPRISING A PAIR OF IMPERVIOUS CONFRONTING ADJACENT WALLS HAVING FLAT INNER FACES AND MATING BAFFLE MEANS THEREON MOVABLE TOWARD ONE ANOTHER WHEN THE CIRCULATING LIQUID ENTERS SAID FILTER THROUGH ONE OF SAID PORTS TO FORM A TORTUOUS FILTER PATH AND MOVABLE AWAY FROM ONE ANOTHER WHEN THE CIRCULATING LIQUID ENTERS SAID FILTER THROUGH THE OTHER OF SAID PORTS FOR SELF CLEANING SAID FILTER. 